

The SASH LOCK comprises of a latch tongue, to be operated by the handle
and a bolt to be operated by a key.
These lock have internal levers which are operated when the key is
turned.
For internal doors a three lever sash lock is usually sufficient.
For external doors you should select a five lever British standard sash
lock. Basically the more levers required to operate the lock the more
secure the lock is.
BS3621 is the British standard covering lock security. The standard is
strongly recommended by the police and insisted upon by most insurance
companies.
The standard ensures that the lock is resistant to attack by drill, saw
or force.
The BATHROOM LOCK comprises of a latch tongue, to be operated by the
handle and a bolt that is operated by a thumb turn and release rather
than a key.
There are two types of latches available: